Deficit Irrigation Affects Tuber Mineral Composition of Four Potato Genotypes

Deficit irrigation (DI) is a sustainable approach to optimize water use while maintaining yield and quality of potato tubers, particularly in arid and semi-arid regions like the Mediterranean. This study assessed the impact of DI on the macro- (Ca, K, P, N, Mg) and micromineral (Cu, Fe, Mn, Na, Zn) element composition of four ‘early’ potato genotypes (G) across two growing seasons (S) in southern Italy. Three irrigation levels were tested: no irrigation ( I 0 ), 50% of crop evapotranspiration (ET c ) ( I 50 ), and 100% of ET c ( I 100 ). Results highlighted the significant influence of DI, G, and S, as well as their interactions (‘DI × G’ and ‘G × S’), on tuber mineral element content. DI was the primary factor affecting Fe, P, and Na levels and the Na/K ratio, while G mainly influenced N content. S had a strong impact on most other minerals. However, the potato genotypes responded differently to DI, identifying the ‘DI × G’ as a key factor influencing the mineral element accumulation. For instance, the I 0 treatment led to higher Ca (+ 33.7%) and P (+ 51%) in ‘Arizona’ compared to I 100 . Conversely, I 100 increased Na levels in ‘Arizona’, ‘Paradiso’ and ‘Vogue’, echoing the trend in Na/K ratio. The principal component analysis also provided valuable insights into the relationships between G and DI treatments. These findings suggest that combining DI with G selection can enhance mineral composition in potatoes while reducing water use, offering a promising strategy for sustainable cultivation in Mediterranean climates.